Add JSON API for changing config by section

app/controllers/api/settings_controller.rb

@@ -0,0 +1,45 @@
+class Api::SettingsController < ApplicationController
+  before_action :login_required
+  before_action :find_fluentd
+  before_action :set_config
+  before_action :set_section, only: [:show, :update, :destroy]
+  helper_method :element_id
+  respond_to :json
+
+  def index
+  end
+
+  def update
+    coming = Fluent::Config::V1Parser.parse(params[:body], @fluentd.config_file)
+    current = @section
+    index = @config.elements.index current
+    @config.elements[index] = coming.elements.first
+    @config.write_to_file
+    head :no_content # 204
+  end
+
+  def destroy
+    @config.elements.delete @section
+    @config.write_to_file
+    head :no_content # 204
+  end
+
+  private
+
+  def set_config
+    # TODO: not found
+    @config = Fluentd::Setting::Config.new(@fluentd.config_file)
+  end
+
+  def set_section
+    # TODO: not found
+    @section = @config.elements.find do |elm|
+      element_id(elm) == params[:id]
+    end
+  end
+
+  def element_id(element)
+    index = @config.elements.index(element) # TODO: not found
+    "#{"%06d" % index}#{Digest::MD5.hexdigest(element.to_s)}"
+  end
+end

app/models/fluentd/setting/config.rb

@@ -4,7 +4,7 @@ class Fluentd
   module Setting
     class Config
       attr_reader :fl_config, :file
-      delegate :elements, :to_s, to: :fl_config
+      delegate :elements, to: :fl_config
 
       def initialize(config_file)
         @fl_config = Fluent::Config.parse(IO.read(config_file), config_file, nil, true)
@@ -26,6 +26,14 @@ class Fluentd
           elm.name == "match"
         end
       end
+
+      def write_to_file
+        File.open(file, "w"){|f| f.write formatted }
+      end
+
+      def formatted
+        fl_config.to_s.gsub(/<\/?ROOT>/, "").strip_heredoc.gsub(%r|^</.*?>$|, "\\0\n")
+      end
     end
   end
 end

app/views/api/settings/_element.json.jbuilder

@@ -0,0 +1,6 @@
+json.id element_id(element)
+json.name element.name
+json.type element["type"]
+json.arg element.arg
+json.settings element
+json.content element.to_s

app/views/api/settings/index.json.jbuilder

@@ -0,0 +1,3 @@
+json.array! @config.elements do |elm|
+  json.partial! "api/settings/element", element: elm
+end

app/views/api/settings/show.json.jbuilder

@@ -0,0 +1 @@
+json.partial! "api/settings/element", element: @section

config/application.rb

@@ -19,6 +19,7 @@ require "jquery-rails"
 require "sucker_punch"
 require "settingslogic"
 require "kramdown-haml"
+require "jbuilder"
 
 module FluentdUi
   class Application < Rails::Application

config/routes.rb

@@ -93,5 +93,7 @@ Rails.application.routes.draw do
     get "file_preview"
     post "regexp_preview"
     post "grok_to_regexp"
+
+    resources :settings, only: [:index, :show, :update, :destroy], defaults: { format: "json" }
   end
 end